This invention relates to industrial robots, and more particularly to the position correction of the hand of an industrial robot.
A number of industrial robots carrying out a series of operations according to a program have been conventionally proposed. For instance, an industrial robot which handles workpieces being moved on the conveyor has been disclosed by Japanese Patent Application Publication No. 21362/1980. In addition, Japanese Patent Application Laid Open No. 80307/1986 has disclosed an industrial robot in which, when it is detected that its hand is out of the predetermined operating area, the operation of the robot is stopped. That is, the conventional industrial robots operate within a predetermined work range according to the program, or the work points of the hand are taught to suitably operate so that the hand operates accurately, which are well known in the art.
In most of the conventional industrial robots, the hands are connected to the arms with bolts. Therefore, if the bolts are loosened, then the hand is displaced, as a result of which the hand may not be able to operate accurately. In addition, in this case, it is necessary to return to the hand to its original position and to teach the locus to the hand again. Sometimes, the hand may be damaged when striking against the work stand.